29 May
2024
29 May
'24
9:48 a.m.
On 5/28/24 22:27, Lars Brinkhoff via cctalk wrote:
However, it's not entirely clear cut. In many
situations data inside
words are arranged "left to right" and in this case the PDP numbering
sometimes is more convenient than the opposite.
The CDC STAR/CYBER machines were bit-addressed. When dealing with bit
strings for the likes of control- and sparse-vectors, it's the only
thing that makes sense, particularly when vectors can be very large.
As the nominal word size of those machines was 64 bits and the preferred
display radix was hexadecimal, it made for some interesting mental
gymnastics when converting between bit, byte, halfword and word
addresses (alignment requirements). The odd fallout from this was that
when a word in memory was addressed, the most significant bit was the
lowest bit address.
--Chuck